The present inventive concept herein relates to semiconductor memory devices, and more particularly, to a nonvolatile memory device, a nonvolatile memory system including a nonvolatile memory device and an operating method of a nonvolatile memory system.
A semiconductor memory device is embodied using a semiconductor such as silicon Si, germanium Ge, gallium arsenide GaAs, indium phospide InP, etc. Semiconductor memory device may be classified into volatile memory devices and nonvolatile memory devices.
A volatile memory device loses its stored data when its power supply is interrupted. Examples of a volatile memory device include a static RAM (SRAM), a dynamic RAM (DRAM), a synchronous DRAM (SDRAM), etc. A nonvolatile memory device retains its stored data even when its power supply is interrupted. Examples of a nonvolatile memory device include a read only memory (ROM), a programmable ROM (PROM), an electrically programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a flash memory device, a phase-change RAM (PRAM), a magnetic RAM (MRAM), a resistive RAM (RRAM or ReRAM), a ferroelectric RAM (FRAM), etc.
To improve the integration of a semiconductor memory, a multi level cell (MLC) that stores at least 2 bits in one memory cell is being used. However, a multi level cell (MLC) has low reliability and a low operating speed as compared with a single level cell (SLC). To extend the life of a memory device and improve the performance of a memory device, a memory device including a SLC and a MLC in one semiconductor memory is being provided.